Nats' New Cathedral to Baseball Prepares for Pontiff

The transformation of Nationals Park into an open-air church for a Mass celebrated by Pope Benedict XVI began yesterday, with workers installing hundreds of thousands of square feet of flooring over the Kentucky bluegrass outfield.

The carpenters, electricians and other workers, 500 in all, weren't able to begin sooner because of the Nationals' game Sunday. On Thursday, the Mass is expected to draw as many as 46,000 worshipers with tickets to assigned seats in the stands and on the field. Tomorrow will be spent in dress rehearsals for the two-hour Mass, and security is being tightened around the ballpark as the week wears on.

Yesterday, tarps were draped over advertising marquees. Thirty semis of equipment were being unloaded. Additional television cameras were being installed. And construction began on the 75-foot-tall altar, which will sit in centerfield with a ceiling and a backdrop of a gold curtain and crucifix.

It was the most visible preparation for the visit of the pope, who arrives today at Andrews Air Force Base. Other plans include deploying about 1,000 D.C. police officers and 300 from Maryland and Virginia during Benedict's four-day stay, his first here as pope.

"I think you're going to see that Nationals Park became a church, if only for one day," Archbishop of Washington Donald W. Wuerl said.

The Secret Service is directing security for the trip, with special emphasis on the pope's visit to the White House tomorrow, his 81st birthday, which will be followed by a drive in the bulletproof Popemobile to the Vatican Embassy on Massachusetts Avenue NW. Thousands are expected to line the route, which will mean several road closures.

There will be other events, not open to the public, at the Basilica of the National Shrine of the Immaculate Conception, Catholic University and the Pope John Paul II Cultural Center.

The FBI has been investigating possible threats to the pope during his visit. He has been denounced by al-Qaeda and its supporters several times in recent years, with Osama bin Laden saying in an audiotape last month that Benedict was involved in a "new crusade" against Muslims. But Joseph Persichini Jr., director of the FBI's Washington field office, said, "At the present time, we have no viable threat to the pontiff" or the places he will visit.

Security for Thursday's papal Mass, the single-largest gathering of Benedict's visit, will include shutting down the Frederick Douglass Bridge and South Capitol Street, which runs along the west side of Nationals Park, from 2 a.m. until 2 p.m. Bomb teams will sweep the ballpark, and everyone attending will have to pass through metal detectors.

No backpacks, video cameras, food or metal, plastic or glass containers will be allowed. "Our recommendation there is to get there early," said Assistant Police Chief Patrick A. Burke, head of the Homeland Security and Special Operations Division for the D.C. police.

At the Nationals' home opener March 30 -- when President Bush threw out the first pitch, the gates were open longer and fewer people came -- some fans waited an hour to get through metal detectors.

The Navy Yard Station is the closest Metro stop to the ballpark. Drivers can park at RFK Stadium for $13 or at the old convention center at Ninth and H streets for $25. Parking passes must be bought online at http://dcpapalvisit.clickandpark.com. More than 160 buses will shuttle people from the lots to the ballpark.